Search Results

With the emergence of stringent emissions standards and needs for fuel diversification, many countries are considering a massive use of natural gas for transportation. In this context, dual fuel diesel-CNG combustion is considered as a promising solution for highly efficient internal combustion engines. This concept offers the possibility to combine a diesel pilot injection as a high energy combustion initiation event, with an indirect injection of methane as main energy source. Low CO2 emissions can be reached thanks to the use of a conventional compression ignition engine with high compression ratio, and thanks to methane's high knocking resistance and low carbon content. Another benefit of dual fuel operation with high diesel substitution rates is the drastic reduction of PM emissions since methane is a very stable molecule containing no soot precursor.

The knock resistance of gasoline is a key factor to decrease the specific fuel consumption and CO2 emissions of modern turbocharged spark ignition engines. For this purpose, high RON and octane sensitivity (S) are needed. This study shows a relevant synergistic effect on RON and S when formulating a fuel with isooctane, cyclopentane and aromatics, the mixtures reaching RON levels well beyond the ones of individual components. The same is observed when measuring their knock resistance on a boosted single cylinder engine. The mixtures were also characterized on a rapid compression machine at 700 K and 850 K, a shock tube at 1000 K, an instrumented and an adapted CFR engine. The components responsible for the synergistic effects are thus identified. Furthermore, the correlations plotted between these experiments results disclose our current understanding on the origin of these synergistic effects.